1. Field of the Invention
This invention relates to an amorphous alloy ribbon for a nanocrystalline soft magnetic alloy, a nanocrystalline soft magnetic alloy made from an amorphous soft magnetic alloy ribbon, and a magnetic core made from a nanocrystalline soft magnetic alloy which is used for various transformers and various reactor choke coils, a noise suppression component, a pulse power magnetic component used for a laser power supply, an accelerator, or the like, a pulse transformer for communication, various motor magnetic cores, various dynamos, various magnetic sensors, an antenna magnetic core, various current sensors, a magnetic shield, or the like.
2. Description of the Related Art
As a soft magnetic material used for various transformers, various reactors, a choke coil, a noise suppression component, a laser power supply, a pulse power magnetic component for accelerators, or the like, a silicon steel, a ferrite, an amorphous alloy, a nanocrystalline alloy, or the like is known. Since a ferrite material has a problem that the saturation flux density is low and the temperature characteristic is bad, a ferrite is magnetically saturated easily and unsuitable for the use of high power designed to become the magnetic flux density of operation large. A silicon steel plate is a cheap material with a high magnetic flux density, but it has a problem that the magnetic core loss is large for the use of high frequency. An amorphous alloy is ordinarily produced from a liquid phase or a vapor phase by rapidly cooling. It is known that an amorphous alloy of Fe group or Co group does not have the magnetocrystalline anisotropy essentially and has an excellent soft magnetic characteristics since a crystal grain is not present, and is used for a transformer iron core for electric power, a choke coil, a magnetic head, a current sensor, or the like. There is a problem that an amorphous alloy of Fe group has the large magnetostriction, however, it does not obtain the high magnetic permeability compared to an amorphous alloy of Co group. There is also a problem that an amorphous alloy of Co group has the low magnetostriction and high magnetic permeability, however, it has the low saturation flux density which is less than or equal to 1 T (Tesla).
It is known that an nanocrystalline alloy shows the excellent soft magnetic characteristic which is equivalent to an amorphous alloy of Co group and the high saturation flux density which is equivalent to an amorphous alloy of Fe group, and is used for a noise suppression component such as a common mode choke coil or the like, a high frequency transformer, a pulse transformer, a magnetic core such as a current sensor or the like. A typical composition system is a Fe—Cu—(Nb, Ti, Zr, Hf, Mo, W, Ta)—Si—B system alloy, a Fe—Cu—(Nb, Ti, Zr, Hf, Mo, W, Ta)—B system alloy, or the like described in Patent document 1 and Patent document 2 are known. These nanocrystalline alloys of Fe group are ordinarily produced an amorphous alloy from a liquid phase or a vapor phase by rapidly cooling and then microcrystallized by heat treatment. It is known that a method of rapidly cooling from a liquid phase is a single roll method, a twin roll method, a centrifugal rapidly cooling method, an in-rotating liquid spinning method, an atomizing method, a cavitation method, or the like. It is known that a method of rapidly cooling from a vapor phase is a sputtering method, an evaporation method, an ion plating method, or the like. It is known that a nanocrystalline alloy of Fe group is microcrystallized an amorphous alloy produced by these methods, and does not almost have the thermal instability which is observed by an amorphous alloy, and shows an excellent soft magnetic characteristic which is the high saturation flux density and the low magnetostriction comparable as Fe system amorphous alloy. It is known that a nanocrystalline alloy has a small change in characteristics with time and also has excellent temperature characteristics.    Patent document 1: Japanese Patent Publication No. H04-004393 (Page 5, column 10, lines 31-43).    Patent document 2: Japanese Patent Laid Open Publication No. H01-242755 (Page 3, left upper column, line 15-right upper column, line 5).